The present invention relates to a method for making diaryliodonium polyhalometalloid salts by reacting a diaryliodonium perchlorate with an alkali metal polyhalometalloid salt.
Prior to the present invention, as shown by U.S. Pat. No. 3,981,897, assigned to the same assignee as the present invention, diaryliodonium polyhalometalloid salts were made by effecting reaction between diaryliodonium bisulfate salt and alkali metal polyhalometalloid salt. Improved results were achieved in Crivello et al. U.S. Pat. No. 4,151,175 employing methylene chloride as a solvent in the reaction in place of acetic acid during the formation of the diaryliodonium bisulfate salt. Although satisfactory results are achieved by the aforementioned methods, a considerable excess of the polyhalometalloid salt, such as potassium hexafluoroarsenate is required in the diaryliodonium bisulfate salt reaction mixture to achieve optimum yields of the diaryliodonium polyhalo metalloid salts. As a result, the diaryliodonium bisulfate route to diaryliodonium polyhalo metalloid salts is economically less attractive because of the significant losses of the polyhalometalloid salts.
The present invention is based on the discovery that diaryliodonium polyhalometalloid salts of the formula, EQU [(R).sub.a (R.sup.1).sub.b I].sup.+ [MX.sub.c ].sup.- ( 1),
can be made by effecting reaction between a diaryliodonium perchlorate and a polyhalometalloid alkali metal salt in the presence of an organic solvent to provide quantitative yields ity of utilizing excess amounts of polyhalometalloid salts, where R is a monovalent aromatic organic radical, R.sup.1 is a divalent aromatic organic radical, X is a halogen radical, such as I, Br, Cl, F, etc., M is a Group IIIb metal or Group Va metalloid, a is a whole number equal to 0 or 2, b is a whole number equal to 0 or 1, the sum of a+b is equal to 1 or 2 and c is an integer equal to 4-6 inclsuive.